Avoid extra lookup in overrideContextData
Avoid extra lookup in overrideContextData

Summary: Title, unecessary cost in case of conflict

Reviewed By: yfeldblum

Differential Revision: D15604536

fbshipit-source-id: ad40c84b822a96a688f810b24b539ac162fdcc59

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly